The latest draft guidance from NICE said that women with oestrogen receptor positive breast cancer that is diagnosed after it has begun to spread will be eligible for palbociclib – also known as Ibrance.

If they have gone through the menopause, they will be eligible for ribociclib – also known as Kisqali.

The two medications are the first of a new type of drug shown to slow down the progression of cancer by inhibiting two proteins – CDK 4 and 6.

They only need to be taken once a day, alongside an aromatase inhibitor – which blocks the production of the hormone oestrogen and can fuel some breast cancers.

Nicholas Turner, professor of molecular oncology at the Institute of Cancer Research in London, and consultant medical oncologist at the Royal Marsden, said the new drugs were “one of the most important breakthroughs for women with advanced breast cancer in the last two decades.”

Prof Turner, who led the clinical trials for the drugs, said: “Palbociclib and ribociclib have made a huge difference to women’s lives – slowing down tumour growth for nearly a year, and delaying the need for chemotherapy with all its potentially debilitating side-effects.